Muffler



Feb. 25, 1947. Y J. p, MARX 2,416,452

MUFFLER Filed Jan. 25, 1945 a2 15 a I INVENTOR. BY L/USEFHE fVAHlX i Patented Feb. 25, 1947 UNITED STATES PATENT OFFICE MUFFLER Joseph P. Marx, Hartford, Wis.

application January 25, 1945, Serial No. 574,569

11 Claims. 1

The invention relates to mufllers, and more particularly to an inexpensively constructed silencer especially adapted for use on the exhaust of low velocity internal combustion engines, gas engineaair motors, and the like.

Known types of mufflers designed to silence the noise of the exhaust of an engine embody various conventional types of construction and assembly in which means is provided, usually in the form or axial and surrounding or intermediate tubular passageways, at least some of which are coextensive with the entire length of the muiiler, interconnected by louvered perforations intended to create a turbulence in the escaping gases and sound waves as they flow from one passageway to the other. Such prior known devices of a kind that may be adapted for use on low velocity motors are highly inefficient and in some instances totally inefifective as silencers, because of their peculiar internal organization which, in most instances, results in the creation of whistli g noises, and their use is therefore not very desirable. Such known mufliers aiso are objectionable from the standpoint of involved and costly assembly. It is therefore an object of the present invention to provide a very efficient exhaust muiller, particularly useful on low velocity engines, of the kind which is inexpensive to construct and assemble, and which may be installed easily and quickly and embodies a minimum of parts.

Another object of the invention is to provide a muiiler with a series of interconnected compartments of a kind having progressively increasing capacities for a portion of the distance traveled by the exhaust gases and sound waves passing therethrough, and progressively decreasing capacities for the remaining distance of travel through said muiiler.

Another object is to provide a muiiler having chambers equipped with novelty shaped baiiles effective to divide said chambers into irregularly shaped compartments communicating one with the other through radial openings in said bafiies.

Another object or" the invention is to provide a low velocity mufller of a kind which causes the gases and sound waves entering therein to be divided into a multiplicity of turbulent nondirectional streams of different values, lengths and velocities so as to absorb and destroy sound Waves of all frequencies and provide maximum efficiency in silencing noises.

Another object is to provide a muffler organization embodying novel features of construction.

Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawing which, by way of illustration, shows a preferred embodiment and the principle thereof, and which is considered to be the best mode contemplated for applying that principle. Other embodiments of the invention embodying the same or equivalent principle may be used and structural changes may be made as desired, by those skilled in the art without departing from the present invention and the purview of the appended claims.

In the drawing:

Fig. l is a perspective view of the improved silencer.

Fig. 2 is a longitudinal central detail View of the silencer.

Fig. 3 is a transverse sectional detail view taken on line 33 of Fig. 2.

4 is a transverse sectional detail view taken on line 44 of Fig. 2.

The silencer embodying the features of the present invent-ion and disclosed in the accompanying drawing is formed or" sheet material, such as sheet steel or metal tubing, and is constructed of a plurality of separate parts, all joined as by welding into an integral self-contained unit having a uniform external appearance. As best illustrated in Fig. 2, the inufiler includes a cylindrical shell or body portion, generally indicated at l 5, consisting of an intermediate tubular portion I2 and two identical end portions H3. The end portions l3 are each substantially cupshaped so as to provide a circumferential wall l4 having the same diameter as the wall or" the intermediate portion 52, and an end wall l'he end wall 15 of each end portion is provided with an axial opening suitably flanged externally as at H5, or otherwise formed, to receive a tubular or like fitting for adapting one end of the muflier for attachment to the exhaust of an engine and the other end for the discharge of gases. In the present instance, one of the end portions 23 carries an externally threaded inlet nipple ll fitted into the flange opening thereof and secured in place as by welding E8, so as to provide an integral leak proof connection. The other end portion l3 has a tubular tail fitting l2 fitted snugly within the flanged opening thereof and firmly secured thereto as by welding at 23.

The margins at the free edges of the circumferential walls :4 of both end portions are flared outwardly to provide an external circumferential flange 2i on each, and the end margins of the intermediate portion 12 similarly are flared enra ed outwardly to provide circumferential external flanges 22. When the end portions R3 are arranged in proper relationship at opposite ends of the intermediate portion !2, the respective complemental external flanges 2! and 22 are brought into registering abutment one with the other, and they are joined together, as by welding, into leak proof circumferential seams 23 to prevent the escape of gases at the joining and to firmly connect the end portions l3 and intermediate portion l2 into a unitary circumferentially reinforced shell structure.

The intermediate portion i2 is fitted with a circular partition Wall 24 which may be flanged, as at 25, to fit snugly within said portion. The partition 25 preferably is firmly secured within the intermediate portion l2 as by spot welding 26, and it is preferred that said partition be spaced closer to one end of the intermediate portion for a purpose to be explained presently. It should be noted at this time that the partition wall 2 divides the shell l i into two chambers of unequal size and that it contains a plurality of port openings 21 so as to afford restricted passageways for the gases from one chamber to the other.

Each of the end portions i3 is provided with a novelly shaped baiile of a kind generally indicated at 28. substantially cup-shaped element including a circumferential wall 29, having a diameter considerably smaller than the inside diameter of the circumferential wall it of the end portion iii, an imperforate end wall 3i, and an imperforate external circumferential mounting flange 32. The mounting flange 32 is formed with an annular lip 33 having an external diameter of such size as to fit snugly within the end portion l3, so that the baffle 28 may be firmly secured within said end portion as by spot welding 34.

The location of the battles 28 within the muffler shell H, with one located on each side of the partition 2d, serves effectively to divide each of the chambers hereinabove referred to into two compartments of unequal capacities. More specifically, a compartment 35 is provided immediately adjacent the end of the mufiler carrying the inlet nipple ll. This compartment has less capacity than the next adjacent compartment identified at while a compartment S'i, located on the other side of the central partition wall 2:: has a r capacity slightly less than the capacity of compartment 36. Similarly, the end compartment 33, next adjacent the tail fitting it), has a capacity less than that of the compartment 37, all for a purpose to be explained presently.

The circumferential wall 29 of each of the cupshaped baffles 28 is provided with suitable apertures 3% preferably in the form of slots, so as to afford connecting passageways between the compartments located on either side thereof.

In use, the nipple I1 is connected in a conventional manner to the exhaust or discharge pipe of the engine to be silenced. The exhaust or discharge gases and attendant sound waves enter the mufiier shell H through said nipple and expand within the compartment 35. The expanded gases and sound waves then flow under pressure radially through the slotted apertures 32? in the related baiile 28, whereupon they expand further upon entering the next adjacent compartment 3%. At this stage of the silencing operation of the muffler, the sound waves are broken up and turbulated to a considerable extent. These expanded exhaust gases and sound waves then fiow through the restricted port openings 27, in partition wall.

As shown, each bafile 23 consists of a 24, and are contracted or compressed slightly upon entering the compartment 3'1, which is considerably smaller than the compartment 36. The gases and any remaining sound waves then flow radially through the apertures 39 in the related baffle 28 into the last compartment 38 and then out through the exhaust tail-fitting if) at substantially the same velocity as they entered the muffler.

The initial expansion and subsequent contraction of the exhaust gases and sound waves and the resultant variances in their velocity and directions of travel causes the sound waves to be out of phase one with another. As a result, most of the sound waves are absorbed and destroyed and sound is eliminated from the gases discharged from the muffler through the tail-fitting I 9.

I claim:

1. A mufller of thetype described, in combination, a cylindrical shell, a flat perforate partition in said shell dividing said shell into two substantially like chambers, each end of said shell having an opening, one communicating with each chamber to provide an inlet and an outlet for exhaust gases and sound waves passing through said chambers, and means in each chamber including a perforate cylindrical wall spaced from the circumferential wall of said shell to deflect the flow of gases and sound waves passing throug said chambers.

2. A muffler 0f the type described, in combination, a cylindrical shell, 2. perforate partition in said shell dividing said shell into two substantially like chambers, each end of said shell having an opening, one communicating with each chamber to provide an inlet and an outlet for exhaust gases and sound waves passing through said chambers, and means in each chamber including a perforate cylindrical wall spaced from the circumferential wall of said shell to divide each chamber into two compartments each having a different capacity.

3. A mufiler of the type described, in combination, a cylindrical shell, a perforate partition in said shell dividing said shell into two chambers, each end of said shell having an opening, one communicating with each chamber to provide an inlet and an outlet for exhaust gases and sound waves passing through said chambers, and means in each chamber including a perforate cylindrical wall spaced from the circumferential wall of said shell to divide each chamber into two compartments wherein one compartment in one chamber has a greater capacity than the corresponding compartment in the other chamber.

4. A mufller of the type described, comprising, a cylindrical shell having inlet and outlet openings at its ends for exhaust gases and sound waves, a perforate fiat partition in said shell between said inlet and outlet openings and through which the gases and sound waves must pass, and baffle means on each side of said partition including a perforate cylindrical wall portion spaced from the wall of said shell adapted to deflect the streams of gases and sound waves passing between the partition and one of said openings radially.

5. A mufller of the type described, comprising, in combination, a cylindrical shell having end walls, a tubular fitting in each end wall communieating with the interior of said shell, a perforate partition in said shell dividing the interior of said shell into substantially alike chambers, a cupshaped bafile having an imperforate external circumferential flange and an imperforate bottom mounted in each chamber, said flanges being joined to the wall of said shell so as to divide each chamber into compartments, and a plurality of passages in the cylindrical wall of each cupshaped bafiie, the cylindrical Walls of said baffles extending in opposite directions and toward the partition.

6. A muffler of the type described comprising, in combination, a cylindrical shell having end walls, inlet and outlet openings for exhaust gases and sound waves in said end walls, a perforate partition in said shell dividing the interior thereor into two cylindrical chambers, short cylindrical members arranged one in each chamber, said members having their cylindrical wall concentric with and spaced from the wall of said shell, an external flange on one end of each member for mounting said member to said shell one closely adaj cent to each end wall thereof, and an imperforate wall at the other end of each cylindrical member, said members having their cylindrical walls perforate so as to enable the ases to flow from the inlet to the outlet opening.

'7. A shell for a muffler, comprising, two like cylindrical end members each closed at one end and having an external flange on its free edge, said closed ends having reduced openings therein for the passage of exhaust gases and sound Waves, an intermediate cylindrical member of like diameter between said end members, an external circumferential flange at each end of said intermediate member to abut the flange on the respective end member, said flanges bein joined to prevent separation of the members and to provide circumferential reinforcement for the shell, and a perforate partition in said intermediate member, said perforate partition consisting of a flat plate and being located on one side of the longitudinal center and entirely within said intermediate member.

8. A shell for a muffler, comprising, two like cylindrical end members each closed at one end and having an external flange on its free edge, said closed ends having reduced openings therein for the passage of exhaust gases and sound waves, an intermediate cylindrical member of like diameter between said end members, and an external circumferential flange at each end of said intermediate member to abut the flange on the respective end member, said flanges being joined to prevent separation of the members and to provide circumferential reinforcement for the shell, a flat perforate partition wall in the intermediate 6 member, and a perforate cup-shaped baiiie in each end member.

9. A shell for a mufller, comprising, two like cylindrical end members each closed at one end and having an external flange on its free edge, said closed ends having reduced openings therein for the passage of exhaust gases and sound waves, an intermediate cylindrical member of like diameter between said end members, an external circumferential flange at each end of said intermeiate member to abut the flange on the respective end member, said flanges being joined to prevent separation of the members and to provide circumferential reinforcement for the shell, and a baffle including a cylindrical wall portion in each end member, said cylindrical wall portion projecting inwardly from the closed end of the end member in which it is mounted being perforated and spaced from the circumferential wall of the end member in which it is mounted.

10. A mufiler having an exterior cylindrical shell closed at its ends and having an inlet opening in one end and an outlet opening in the other end, a substantially centrally located perforated partition wall between said ends, and two oppositely facing substantially cup-shaped baifles including cylindrical portions concentric with the shell arranged in said shell, said two baffles being disposed one on each side of the partition.

11. A mufiier having an exterior cylindrical shell closed at its ends and having an inlet opening in one end and a outlet opening in the other end, a substantially centrally located perforated partition wall between said ends, and two oppositely facing substantially cup-shaped baffles arranged in said shell one on each side of the partition, said cup-shaped bafiles each consisting of a perforate cylindrical portion closed at the end disposed towards the partition and having an external imperforate flange at its other end.

JOSEPH P. MARX.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 779,024 Buchner et al Jan. 3, 1905 1,839,192 Baits Jan. 5, 1932 2,218,063 Munzer Oct. 15, 1940 2,054,324 Hollerith Sept. 15, 1936 

